A variety of different styles of conveyor systems utilizing a flexible belt that moves in three dimensions through a curved path have heretofore been provided and afford several features and advantages over other types of known conveyors presently in use for moving materials. A conveyor system of the type described herein has a flexible, material-supporting belt designed and supported to pass in three dimensions through curves wherein there is utilized a track, a pulling member and a plurality of spaced roller carriages affixed between the belt and pulling member. The movement in three dimensions refers to the capability of the belt moving up and down, laterally, and with substantial rotation about its longitudinal axis along the course of travel through a curved path while supporting the load from below the load. The features and advantages of a conveyor system of the present invention over other types commonly in use include the capability of negotiating horizontal, vertical and spiral curves, moving goods up relatively steep grades, the provision of side discharges without sloping or slowing of the conveyor and the capability of carrying loads in either direction.
In prior known conveyor systems presently in use, there is provided a track with both inside and outside track surfaces, a track pulling chain or the like and a plurality of roller carriages affixed at spaced intervals between the belt and the pulling chain, the carriages and in turn the belt being moved by the movement of the pulling chain with the roller surfaces and chain being exposed to corrosive and abrasive materials and the like. Each roller carriage has four rollers arranged two on each side of the pulling chain, one roller on each side of the chain has its axis disposed horizontally and the other roller has its axis disposed vertically. The horizontal rollers bear on the bottom flanges of the track while the vertical rollers bear on the outside track surfaces. In this arrangement, the roller carriages are relatively heavy and are usually spaced at about one roller carriage for each five belt sections leaving a substantial space between roller carriages.
With a roller arrangement in which there are pairs of both inside and outside rollers relative to the track, the bottom surface of the track is the only surface on which support legs and other support structure can be affixed. Moreover, the wall thickness of the track has to be within certain limits and in some instances a very thick track wall is necessary for special features such as a side discharge or the like. This prior art arrangement does not provide for the taking of the roller carriage out of the track except when a tension or drive station or a combination thereof are provided. The rollers and chain located outside the track result in an abrasive material or other undesirable corrosive or foreign materials being free to enter between the roller and the chain links resulting in undue wear on the rollers surfaces and the chain links. Moreover, with a roller arrangement disposed outside the track the roller carriage has to have additional structure to hold the rollers so that the roller carriages become relatively heavy. In arrangements where there is substantial spacing between roller carriages there is a limit as to the radius curves and substantial tension is required on the chain to avoid undue sagging.
Accordingly, it is an object of this invention to provide an improved conveyor system that will readily move in three dimensions along a curved path.
Another object of this invention is to provide an improved conveyor characterized by a unique construction and arrangement of roller carriage and rollers in which the rollers exert lateral and vertical thrust against the track entirely from within the track against the inside surfaces of the track.
Yet another object of this invention is to provide an improved conveyor system characterized by smaller and lighter roller carriages using more per length of belt that will travel around smaller radius curves and requires less chain tension and had less chain sag between roller carriages.
Yet a further object of this invention is to provide a novel conveyor system in which there are no external carriage rollers but the rollers and the pulling chain are entirely within the track and inside of the track is closed off to provent abrasive and like foreign materials from affecting the bearing surfaces supporting the carriage rollers and the pulling chain links.